Abstract 14872: Sensitivity of Cinefluoroscopy Compared With Visual Inspection of the Extracted Lead for Detection of Conductor Externalization of Riata/Riata St ICD Leads

Abstract

Background: The Riata/Riata ST implantable cardioverter defibrillator (ICD) lead series (St Jude Medical, Sylmar, CA) is vulnerable to a characteristic insulation failure mechanism which results in conductor externalization (CE). This may be visible on cinefluoroscopy, however the sensitivity of this test is unknown when compared with direct visible inspection of extracted leads. Methods: We retrospectively reviewed the records of patients with Riata leads extracted at our center since 01/01/2011, and compared CE on fluoroscopic imaging before extraction with the visual appearance of the extracted lead ex vivo. Cinefluoroscopy of the Riata lead was performed in three planes: posteroanterior, left and right anterior oblique. CE was defined as a conductor that had breached the outer insulation material and was clearly visible outside the lead body on fluoroscopy. Ex vivo, CE was defined as externalization of the conductor cable(s) visible on inspection of the extracted lead with a corresponding linear insulation defect. Results: Of 424 patients with Riata leads 37(8.7%) patients underwent extraction with a mean implant duration of 6.24 years ±1.9 years. The indication for extraction was infection in 12 (32.4%); 7 (18.9%) for electrical or structural lead failure and other indications in 18 (48.6%). CE was evident on cinefluoroscopy in 8 (21.6%) patients before extraction including 2 (25%) leads extracted for electrical failure. Post extraction, CE was visible in an additional 3 (8.1%) leads including 1 (33%) extracted for electrical failure. Overall sensitivity was 72.7%. Conclusions: Cinefluoroscopy has suboptimal sensitivity for detection of CE in Riata ICD leads. The absence of CE on cinefluoroscopy does not imply that the outer insulation is structurally intact. Our results suggest that routine cinefluoroscopy of Riata/Riata ST leads is of limited utility.